Dental training device

ABSTRACT

A dental training aid and method which assists a student in learning how to determine the position of a root canal apex, repair of dental decay, and how to perform crown and bridge procedures. In certain embodiments, modular inserts are utilized that include structure thereon for performing root canal procedures, repair of dental decay procedures, crown and bridge procedures or other procedures. The inserts can be assembled and configured to all provide practice on the same procedure or on different procedures and can be exchanged for other inserts once they are no longer reusable or because the user wants to train on a different procedure.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of prior U.S.application Ser. No. 11/297,248, filed Dec. 9, 2005, now abandoned whichwas a continuation-in-part of U.S. application Ser. No. 10/767,793 filedJan. 29, 2004, entitled DENTAL TRAINING DEVICE, now U.S. Pat. No.6,988,894 which was a continuation-in-part of prior application Ser. No.10/024,683 filed Dec. 18, 2001 and entitled DENTAL TRAINING DEVICE, nowabandoned, which was a continuation-in-part of prior application Ser.No. 09/848,739 filed May 3, 2001 and entitled DENTAL TRAINING DEVICE,now U.S. Pat. No. 6,520,775.

BACKGROUND OF THE INVENTION

The present invention related to dental equipment, and moreparticularly, to teaching tools for the use of endodontic apicallocation equipment.

During certain dental procedures, the pulp of the tooth must be removedand other procedures must be performed on the root canal. Personstraining to become dentists must learn how to properly remove such pulpand perform the other necessary procedures. Precise location of the rootapex is vitally important for the correct endodontic treatment of atooth. Pulp tissue is richly vascularized and innervated and iscontained in the pulp cavity inside the tooth including in the pulpchamber and in pulp canals in tooth roots. The pulp canals are oftenreferred to as root canals. If the endodontic procedure of extractingand cleaning the pulp tissue from a root pulp canal is performed at alength short of the apex, pulp tissue may remain in the canal. Failureto remove all pulp tissue may lead to infection and pain for the patientand necessitate additional surgery. If the endodontic procedure isperformed beyond the length of the root apex, the reamer may penetrateinto the periodontal ligament leading to pain and extreme sensitivity tothe patient. Therefore, current endodontic procedures normally requirethe careful locating of the root apex at the base of the pulp canalbefore the reamer or other tools are used to enlarge the pulp canal.

Multiple methods are currently utilized to determine the location of theapex during an endodontic procedure on a live patient. One procedure isthe use of x-ray radiographs of the tooth while a metal endodonticreamer is located in the root canal. This allows the dentist to visuallycompare the length of the metal reamer to the location of the end of theroot to determine the location of the root apex. This method is oftenunreliable and not cost-effective.

A second method is to use an electrically aided apical positionlocation. Certain electronic aids and methods of their use include thosedescribed in U.S. Pat. No. 5,759,159 to Masreliez, U.S. Pat. No.5,211,556 to Kobayashi et al, and U.S. Pat No. 6,059,569 to Otsuka, allincorporated herein by reference. These patents describe apical positionlocators utilizing impedance measurements to determine the location ofthe apex that use electrical conductance. In the electrical conductanceapproach, an electrically-conductive probe is inserted into the rootpulp canal and a second electrode is attached to the patient's body,such as by hanging a hook-shaped electrode from the patient's mouth. Asthe probe is inserted into the root pulp canal and advanced through theroot pulp canal to the root apex, the electrical impedance between theprobe and the electrode is continuously measured. The electricalimpedance is greater when there is little conductance between the probeand the electrode; such as when the probe is in the pulp canal, andlower when there is greater conductance between the probe and theelectrode, such as when the probe touches the tissue at the bottom ofthe pulp canal that is much more conductive than the pulp canal itself.Once the impedance lowers and reaches a predetermined range or value,the location of the apex is indicated and the depth of the probe isnoted for future use with other instruments. The electrical approachusing impedance for determining apex location is currently the preferredand standard technique used in endodontic practice and taught in dentalschools.

Instruction in the use of electrical apical position locators hasgenerally required practice upon live patients in need of endodontictreatment. Performing endodontic procedures on healthy teeth isunethical and represents dental malpractice. Endodontic patients areoften in pain prior to seeing the dentist, and are usually apprehensiveabout the endodontic procedure and less than enthusiastic about servingas subjects in dental instruction on the use of apical positionlocators. The additional pain which may be encountered, or the merepotential for such additional pain, results in few such patientsvolunteering to allow students to perform the procedure.

The number of endodontic procedures that a dental student or a doctoralstudent in general dentistry performs on live patients is severelylimited by the number of willing participants in need of suchprocedures. Dental students and general dentists would benefit fromadditional training and instruction in the use of apical positionlocators in a realistic setting. In turn, the endodontic patient wouldbenefit from the additional training received by the practitioner.

Prior to this invention, no adequate surrogate for the live patient hasbeen developed for instruction in the use of electrical apical positionlocators. U.S. Pat. No. 5,503,562 described a transparent endodonticinspection block which allows the dental student to simulate thecleaning out the root pulp canal. The student utilizing the inspectionblock could look through the side of the inspection block and locate theroot apex. This invention is not designed to train apex locationtechniques and does not represent realistic conditions of endodontictreatment. U.S. Pat. No. 4,137,633, issued in 1979, disclosed aresilient mass located at the apex of a block of transparent material tosimulate the tactile sensation of the periodontal membrane located atthe apex of a natural tooth. Thus, prior devices permitted students tovisually locate a simulated apex through the addition of a resilientmass located at the apex. However, no known prior devices have disclosedproviding a simulation of a live tooth and human tissue to practiceusing an electrical apical position locator.

Additionally, during training to do such procedures, it is important tohave the procedure simulated on an actual patient, as much as possible,so that the student can learn how to overcome problems of working in thepatient's mouth. Therefore, it is also desirable to provide a trainingdevice that can be utilized for at least some of the student endodonticprocedures and which simulates a live patient, as much as possible.

In addition to the need for a training device for use in teaching rootcanal procedures, it is also desirable to have such a device that can beused to teach other types of procedures such as how to treat dentaldecay and how to do crown and bridge procedures. Because trainingdevices may be expensive for the student, it is preferable that thedevice allow the student to practice different types of procedures whichpreferably require somewhat different structure. Root canal proceduresrequire real or artificial teeth having a root and with structureallowing electrical conductance. Crown and bridge work require a sectionof teeth wherein one or more is missing and real or artificial teeth canbe modified to accept a bridge with a skin like structure over the gum,as it is important for the student to correctly interface the bridgewith the skin. Dental decay procedures do not require a root orelectrical conductance, but preferably utilizes real or artificial teeththat are mounted in such a manner so as to simulate the interaction ofthe teeth with each other and with ligament tissue that normally holdssuch teeth in place. Each of these and other procedures are preferablyperformed on separate or different practice units to allow the studentthe best range of training.

Furthermore, it is desirable that the different sections be modular sothat a student can preform one, two or all procedures within a singleassembly. For example, when working on one procedure, all the individualmodular inserts in an assembly may be designed for a single procedure toprovide multiple locations to practice or such can be changed to providemodular inserts for multiple procedures for practice or testing. Becausethe individual modular inserts can be easily changed, when one is usedand is not reusable, it can easily be replaced by another withoutrequiring that the entire assembly be discarded.

SUMMARY OF THE INVENTION

The present invention provides an improved device and method for thetraining of the use of an apical position locator. The invention uses areal or replicated tooth with a root and a root pulp canal (oftenreferred to as a root canal) having an apex at the root tip. Real teethwith pulp in the root canals are available from a supply of such teethremoved from patients for other reasons or from cadavers. In the presentinvention a student practices on a tooth set in a hard medium whichmimics the electrical impedance of human tissue so that an electronicapical locator may be used. In a first embodiment, the tooth is mountedin a single, rigid conductive medium which mimics the conductivity andimpedance characteristics of human tissue. An alternative embodimentuses a first highly conductive medium wrapped around the root tip tocover the apex of the tooth which is then surrounded by a second rigidmedium so as to set the tooth in a fixture containing the second medium.The second medium may be less conductive and holds the tooth suitablyfor manipulation training purposes.

An electronic apical position locator has one lead connected to anendodontic probe or reamer and the other to an electrode blade extendingfrom the medium. When the reamer is inserted in the root canal andextended so that the reamer tip contacts the conductive medium at theroot apex, the electronic circuit of the apical position locator isclosed, the impedance is measured and the apex is appropriatelyindicated by the apical position locator.

In another embodiment of this invention, the tooth is mounted in amanikin jaw that simulates a working human jaw. Preferably, the manikinjaw has sockets at various locations that are located whereat variousteeth would normally be found. Each tooth upon which the student is totrain is mounted in an electrically conductive medium that has a lowerimpedance than the training tooth root canal and which desirably hasapproximately the conductance or impedance of tissue found around thenatural live root apex. A highly conductive medium is preferably placedin a protective sleeve and a second medium or matrix is placed about thetooth within a sleeve and then allowed to harden. The sleeve is sizedand shaped to be received in one or more of the sockets. The sleeve maybe held in place by a pin, such as a thumbscrew or similar fastener,that also acts as an electrical conductor in contact with the conductivematerial in the sleeve and in turn is electrically connected to anelectrode of an apex location apparatus. The entire matrix may be ahighly conductive medium or a less conductive medium may be usedexternally relative to the sleeve. Further, if the pin connects directlywith the highly conductive medium in the sleeve, the remainder of thematrix does not have to be conductive.

A more detailed understanding of the invention will be obtained from thefollowing description of the preferred embodiments taken in conjunctionwith the attached drawings.

This invention provides an actual or replicated human tooth with anelectrically equivalent replicated human tissue medium, especially in ahuman form manikin, to provide a realistic simulator for training in theuse of an electrical apical position locator. Patient volunteers do notnormally clamor for dentists-in-training to practice root canals uponthem, so this invention allows the dental student the opportunity topractice in a realistic environment, preferably with real teeth havingpulp in the root canals thereof. The user may select a partiallyradiopaque electrically conductive medium, which allows the student toalso simulate the determination of the location of the root apex throughthe use of an x-ray radiograph.

In yet another modification of the invention, the training aid isprovided with modular inserts that mimic various portions of the jaw andwhich can be easily exchanged with other inserts that mimic the sameportion of the jaw. In this manner, the inserts can include one or moreunits for training for particular procedures such that all of theassembled inserts may be for the same procedure or for differentprocedures. Each insert can be easily replaced by another for the sameor a different procedure.

Different inserts may be advantageous for many different procedures. Forexample, the inserts may be especially designed to act as an instructionaid for root canal procedures, repair of dental decay procedures, forcrown and bridge procedures or for other procedures. The root canalprocedure inserts are preferably of the type described above with theadded feature of providing a common electrical conductor for the entireinsert support structure so that electrical conductance will beavailable whether none, one or multiple inserts are for root canalprocedures. The dental decay procedure inserts preferably includestructure to allow teeth to be mounted in a matrix that mimics thesetting of live teeth relative to ligaments that support and hold liveteeth, so the student more closely encounters the feel of working onlive teeth, especially crowding by adjacent teeth and flexing underpressure. The crown and bridge procedure inserts preferably include anartificial skin layer that mimics a patent's skin, so that the studentgains experience in mounting crowns and bridge relative to skin tissue.

Certain embodiments of the invention provide a plurality of inserts thatare removably secured to a receiving tray by screws, magnets or the likein an abutting manner so as to simulate a gum line of a human mouthwhile providing at least one actual or replicated tooth upon which apractitioner can perform a dental procedure.

OBJECTS AND ADVANTAGES OF THE INVENTION

Therefore, the objects of the present invention are: to provide atraining aid for dental students comprising a holder or fixture forholding a tooth in a solid medium or material that is at least in partapproximately as electrically conductive as non-boney tissue found inhumans that surrounds teeth so as to simulate the electricalconductivity or impedance found in such tissue and thereby allowing astudent to perform practice root canal procedures, including practicewith an electrical apical position locator, without need for livingpatients; to provide such a training aid wherein the fixture is anindependent container partially filled with solid electricallyconductive medium or material that simulates the electrical conductivityor impedance of human tissue surrounding teeth; to provide analternative embodiment of such a training aid wherein the fixtureincludes a socket in a manikin that simulates a human jaw structure; toprovide such a training aid wherein the sleeve is sized and shaped tofit in such a manikin socket to allow easy removal and cleaning afterthe training session is complete; to provide an alternative manikintraining aid wherein teeth with a highly conductive media about the roottips thereof are molded directly into the manikin; to provide such atraining aid wherein a thumbscrew is used as a pin to secure such asleeve in a socket and wherein the thumbscrew also functions as anelectrode for the apical position locator; to provide such a trainingaid that includes a set of modular training inserts wherein such insertscan be exchanged for similar or different inserts to form a trainingassembly; to provide such a training aid that provides such insertswherein each insert is especially adapted to particular procedures, suchas treatment of dental decay procedures, root canal procedures and crownand bridge procedures; to provide such training aid wherein all of theinserts in a final assembly may be selected for training on the sameprocedure or for different procedures to meet the needs of the studentusing the training aid; to provide a method of training aspiringdentists in endodontic procedures using the aforementioned training aidssuch that the students become skilled without having to practice on livepatients; to provide such a training aid having inserts removablysecurable to a receiving tray and abutting one another so as to form agum line of a simulated patient; and to provide such training aids thatare easy to use, comparatively inexpensive to make and especially wellsuited for the intended purpose thereof.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention.

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a training aid in accordance withthe present invention.

FIG. 2 is a cross-sectional view of a first alternative training aid.

FIG. 3 is a cross-sectional view of the first alternative embodiment ofthe training aid shown in connection with an electronic apex locator.

FIG. 4 is a perspective view of a second alternative training aid inaccordance with the present invention, illustrating a training procedurebeing performed and with portions broken away to show internal detailthereof.

FIG. 5 is an enlarged cross-sectional view of a sleeve, tooth and highlyconductive medium during a first step in assembly of the secondalternative training aid.

FIG. 6 is an enlarged cross-sectional view showing a second stepsubsequent to the first step shown in FIG. 5 in the assembly of thesecond alternative training aid.

FIG. 7 is an enlarged cross-sectional view of the second alternativetraining aid showing a third step in assembly thereof.

FIG. 8 is an enlarged cross-sectional view of the second alternativetraining aid fully assembled and shown in a fragmentary manikin as shownin FIG. 4.

FIG. 9 is an exploded perspective view of a third modified training aidaccording to the present invention having a plurality of modular insertswherein each insert is utilized for training a student with respect to adifferent dental procedure.

FIG. 10 is a perspective view of the third modified training aid withinserts assembled.

FIG. 11 is a perspective view of the third modified training aid showingthe assemblage being prepared for and during specific dental trainingprocedures.

FIG. 12 is a fragmentary cross-sectional view of the third modifiedtraining aid, taken along line 12-12 of FIG. 10.

FIG. 13 is a fragmentary cross-sectional view of the third modifiedtraining aid, taken along line 13-13 of FIG. 10.

FIG. 14 is a plan view of a jaw dental training aid with retainermechanism.

FIG. 15 is an elevational view of the training aid shown in FIG. 14.

FIG. 16 is a fragmentary, exploded and perspective view of a fourthmodified training aid in accordance with the present invention.

FIG. 17 is a fragmentary side elevational view of the fourth modifiedtraining aid with portions broken away to show detail thereof.

FIG. 18 is a fragmentary, exploded and perspective view of a fifthmodified training aid and in accordance with the present invention.

FIG. 19 is a fragmentary side elevational view of the fifth modifiedtraining aid with portions broken away to show detail thereof.

DESCRIPTION OF THE PREFERRED AND ALTERNATE EMBODIMENTS

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

First and Second Embodiments

Referring to FIG. 1, the reference numeral 1 generally indicates atraining device according to the present invention which is useful tocreate an effective simulation of a tooth in a patient, so that astudent may practice using an electronic apical position locator. Thetraining device 1 consists of a tooth 2 which may be an extracted humantooth or a replica, which is set in a fixture 3 and connected to anapical position locator 4, FIG. 3, as hereinafter described. In moredetail, an illustrated exemplary tooth 2 is a pre-molar with two roots10, each with a root canal 11 ending at an apex 12 near the tip 13 ofeach root. Other tooth forms are equally suitable. In a live tooth, theroot canal 11 is filled with nerve pulp tissue. Also, a live tooth isset into a periodontal ligament which surrounds the root 10 and acts asa barrier between the tooth root and the bone that holds the tooth. In apatient the periodontal ligament or tissue around the tooth is moist andelectrically more conductive than the tooth, thereby enabling the use ofan electronic apical position locator 4 which relies on the measurementof impedance to determine when the more conductive tissue is encounteredand therefore when the apex is reached. When the measuring probeelectrode approaches the apex, the magnitude of impedance or the phaseangle of the impedance between the measuring probe and oral probeelectrode starts to change. The detector identifies the apex when thedesignated range or the frequency of impedance is reached.

In the illustrated example, the tooth 2 is a “dead” tooth which has beenextracted from a patient or cadaver and is not supported by a livingperiodontal ligament or other live conductive materials. As shown inFIG. 1, the tooth 2 is set in a container or fixture 3 which is selectedfor ease of manipulation by a student. Preferably, a single settingmaterial 15 is selected which provides sufficient rigidity to supportthe tooth 2 during handling and during the practice of root canalprocedures. Ideally, the selected material 15 should also replicate therange of impedance of live human tissue in order to provide an impedancein the range of the apex locator setting. Since there are many differenttypes of apex locators on the market, a single conductive materialhaving an impedance not in the range of live human tissue can also beused for some apex locators of simple design and it is foreseen that aconductive material could be selected for a specific locator. Generally,the selected material 15 should replicate the conductivity of live humantissue in order to provide an impedance generally matched to theimpedance of live tissue. Because an electric apex locator of advanceddesign contains circuitry and components to measure the impedance ofhuman tissue and then compare the impedance value to the impedancevalues obtained by a measuring electrode inserted into the root canal, acloser match of impedance between the material 15 and the circuit of theapical locator 4 in the locating of apex is normally preferred. Asuitable range for the volume resistivity of the medium 15, 20 and 22supporting the tooth 2 in the fixture 3 is in the range from 10¹⁵ to10⁻³ ohm/cm.

To obtain a suitable support medium, conductive material is mixed withdifferent binders. Such a binder can be plastic resin, polymer resin,plaster, stone, clay etc. Various types and concentrations of conductivematerials in the binder have been conceived and include carbon, carbonfiber, graphite, silver powder, metal or metal coated fiber or powder orflakes, silicon, silicon dioxide, germanium, selenium, conductivepolymer and others in slight to significant concentrations. If aradiopaque support medium can be tolerated, then a high metallic contentor radiopaque chemical such as barium sulfate or stainless steel fibersor powder are usable with a binder. If radio transparency is needed,then metallic content is limited and carbon or other non radiopaquematerials are increased to a proportion balancing strength, conductivityand human tissue impedance. The attribute of impedance matching isintended to bring impedance values into a range sensed by the circuit ofthe electronic apex locator.

A second embodiment of the present invention is shown in FIGS. 2 and 3and uses two conductive medium components. The second embodiment isessentially the same as the first embodiment described above except fora modification to the medium supporting the tooth and is thus numberedthe same except for this medium. In particular, in the secondembodiment, a first conductive medium 20 is applied to the root tip 13to cover the apex 12, generally in a ball about the root tip 13. Whenapplying the first conductive medium 20 to the root tip 13, care isexercised so as not to pack the medium 20 into the canal 11, but tomerely cover the apex 12 as it intersects with the root 10. Thepreferred material of the first conductive medium 20 is a water based ora highly conductive material. The first conductive material or medium 20can be a mixture of water, alginate, agar, gum, clay or a highlyconcentrated carbon or metal powder that is a very good electricalconductor in plastics, especially acrylics, or a mixture with a calciumor sodium inorganic salt, such as calcium sulfate.

The tooth with its root tip coated with the first conductive medium isplaced in a second conductive medium 22 which fills the fixture 3 andwhich is initially soft or even liquid. The second conductive medium 22is preferably then set or hardened to form a solid support for the tooth2. Settling can be accomplished by allowing the medium to dry, whereappropriate, allowing it to chemically set such as an epoxy or acrylic,heat setting the medium 22, where it is capable of being heat set, orthe like. The second medium 22 is preferably mixed with a conductiveelement as mentioned before, typically a resin type material, so that itcan hold the tooth 2 in place for handling and practicing root canalprocedures, after being hardened or set.

The first conductive medium 20 and the second conductive medium 22 maypossess radiopaque material, if training utilizes radiographs tosimulate use in a real patient. Such radiopaque material may includematerial such as metal fibers, metal-coated fibers, carbonaceousmaterial, metallized glass or barium sulfate, as a substantial componentof the medium 22 in sufficient amount to produce radiopaqueness. Thefirst conductive medium 20 and the second conductive medium 22 maypossess materials of differing radiopacity to simulate the differentradiopacity of the periodontal ligament and the bone in a patient.

FIG. 3 shows the training device 1 in connection with an apical positionlocator 4. To enable the training device 1 to be utilized with theapical position locator 4, a measuring probe such as an endodonticreamer 25 is connected to the apical position locator 4 via leads 26 anda connector, such as an alligator clip 28. The apical position locator 4is connected to the conductive medium such as the second conductivemedium 22 via lead 30 and a connector such as an alligator clip 32,connected to an electrode or probe 34 set in second conductive medium22. In the illustrated example, apical position locator 4 indicates theclosure of an electronic circuit when the endodontic reamer 25 contactsor almost reaches the conductive medium 20 at the apex 12. Then theresistance or impedance of these materials are measured, compared andcalculated based on the pre-set formula in the apex locator. A finalreading will indicate reaching the apex by the tip of the dental reamer.Normally, the apical position locator possesses sufficient sensitivitythat it can determine the distance between the tip of the endodonticreamer 25 and the apex 12 and the locator provides a visual readout ofthat distance.

In the practice of the invention, a tooth such as an extracted humantooth 2 is used to train a user by placing the tooth 2 into a containeror fixture 3 and supporting the tooth 2 therein by a conductive medium,such as the single medium 15 shown in FIG. 1. Alternatively, a firstconductive medium 20 can be molded around the root tip 13, being carefulnot to enter the canal 11. Next, the tooth 2 with first conductivemedium 20 wrapped around the root 10 is placed in second conductivemedium 22 in the fixture 3. The second conductive medium 22 is allowedto set so that it firmly holds tooth 2 in place. The apical positionlocator 4 is connected to the endodontic reamer 25 and the probe 34 sothat when the reamer 25 is placed in the root canal 11 and the reamertip contacts the first conductive medium 20 or single medium 15 (FIG. 1)at the apex 12, the locator electronic circuit completes the measurementof electronic resistance or impedance and the apical position locator 4so indicates. Importantly, the resistance of the conductive medium isselected so that the electronic apical locator measures the resistance.

Optionally, the training device may be utilized along with x-raymachines and radiographic film to simulate the verification of thelocation of the apex 12 through simulation of the relative radiopacityof the periodontal ligament and bone by utilizing differing levels ofradiopaque materials in the first conductive medium 20 and the secondconductive medium 22.

Various forms of conductive media may be used as desired includingthermoplastic resins, acrylic, polymers and plasters with fillers suchas carbonaceous material or metal fibers or flakes.

Third Embodiment

Illustrated in FIGS. 4 through 8 is a third embodiment of a dentaltraining device in accordance with the present invention that isgenerally represented by the reference numeral 100. The training device100 has certain aspects that are similar to the devices that areillustrated and disclosed in the previous embodiments and reference ismade to those embodiments for certain details such as materials ofconstruction.

The training device 100 generally comprises a manikin 110 having atleast one socket 111 and, unlike the previously disclosed embodiments,includes a sleeve 112 operably received in the socket 111 and withinwhich a tooth 113 is mounted in a generally solid matrix 114.

The manikin 110 is preferably a type of device which is sometimes alsoreferred to as a typodent that is utilized in the training of dentalstudents. The manikin 110 has an upper jaw or maxilla 120 and a lowerjaw or mandible 121 that are mounted on a support frame 122, such thatthe jaw 120 can be articulated with respect to the jaw 121 in a mannerthat is similar to that of a human jaw, so as to simulate a human jawfor purposes of training of a dental student. The jaws 120 and 121 havea plurality of real and/or simulated teeth 126 that are positioned aboutthe facing surfaces of the jaws 120 and 121 in such a manner as tosimulate the appearance of teeth in a typical human dental patient. Thejaws 120 and 121 are constructed of a material that can vary, dependingupon what is desired to be taught to the students, but which istypically a rigid or semi-rigid plastic that has the shape andappearance of the gums and mouth of a human.

As will be discussed below, the material of construction of the jaws 120and 121 may in some cases be an electrically conductive material thathas conductivity quite similar to the gums and mouth tissue of a humanpatient or may alternatively be constructed of a non-conductivematerial. The material of construction of the jaws may also beradiolucent or radiopaque depending on whether x-ray procedures are tobe used. As is seen in FIG. 4, the upper jaw 120 of the presentembodiment is hinged on the support frame 122 and is biased to a closedposition by springs 128 wherein the teeth 126 of the upper jaw 120engage similar teeth of the lower jaw 121. This simulates a patient witha mouth that can be opened and in which a student must work to performprocedures using the device 100.

The sockets 111 are provided in the jaws 120 and 121 at locations whereit is desirable to provide training to a student learning endodonticprocedures. In the illustrated embodiment such sockets 111 are providedin the lower jaw near the rear where a large molar would be normallylocated and which is illustrated by broken away portions in FIG. 4.Sockets 111 are also provided in other locations such as are illustratedin the upper jaw 120 where somewhat more forward teeth are normallylocated. A training procedure is illustrated in FIGS. 4 to 8 withrespect to an upper jaw socket 111, such as is shown in FIG. 4. Eachsocket 111 is sized and shaped to receive a sleeve 112 snugly therein.Each of the sockets 111 has a shape that is somewhat in the form of ahollow truncated cone and is accessible from the rear of each jaw 120and 121 opposite the teeth 126 (see FIG. 4).

As is best shown in FIGS. 5 through 7, each sleeve 112 has a generaltruncated conical shape with a thin wall 129 and has a hollow interiorso as to form a cavity 130 with an open upper end 131 and open lower end132. The cavity 130 has an interior surface 133. The sleeve 112 is sizedand shaped to receive a tooth 113 and combined form an insert 134. Suchan insert 134 is shown in phantom lines in FIG. 8 prior to placement inthe socket 111 wherein the insert is shown in solid lines.

As has been described with the previous embodiments, the tooth 113 ispreferably a human tooth that has been removed from a live patient forsome other reason or is a tooth that has been harvested from a cadaver.In certain instances where a human tooth is unavailable, an artificialtooth that is sized and shaped to mimic a real tooth may be used. Such atooth 113 includes a pulp chamber 137 and at least one root pulp canalor root canal 138 that extends along each root 139 of the tooth 113.Normally, such a tooth 113 would include pulp 141 intact in the rootcanals 138 and pulp chamber 137. The root canals 138 containing the pulp141 extend to an apex or tip 143 of each root 139.

The practice tooth 113 extends outwardly from the sleeve 112 such that acrown 146 of the tooth 113 is exposed and the tooth roots 139 arelocated within the sleeve 112. The tooth 113 is snugly and rigidly heldin its associated sleeve 112 by the matrix 114. In the presentembodiment, the matrix 114 has two components 148 and 150.

The first matrix component is a relatively good electrical conductorthat is chosen to simulate the electrical conduction found in humantissue in the ligament and gum surrounding a live human tooth. Thehighly conductive matrix component 148 can be any of the materials thathave been discussed in the previous embodiments for such a component.

In the present embodiment the highly conductive component 148 is amalleable or semi-solid material that is molded about each root tip 143.Because the material is soft and can be stripped from the root 139accidentally, a protector 149 is placed over the highly conductivecomponent 148. In the present embodiment the protectors are annularsleeves 151 that are placed over each tooth root 139, as is shown inFIGS. 5 and 6. The highly conductive component 148 is specificallydesigned to provide good conductance at each root tip 143. Each sleeve151 is manually snugged against a respective root 139 and about thehighly conductive component 148 to hold the latter in touch with arespective root tip 143. It is foreseen that other forms and shapescould be utilized for the highly conductive component 148 such as a cupor the like and without a protector.

The second component 150 of the matrix 114 can be several differenttypes of materials depending on whether or not it is desired for thecomponent 150 to also be highly conductive or for conduction to betransferred from the highly conductive component 148 to the locatingdevice described below through some other structure. Consequently, it isforeseen that the matrix component 150 can either be a highly conductivematerial similar to that of component 148, a semi-high conductivematerial that would be useful in providing conduction between thecomponent 148 and a locator or alternatively, may not be conductive atall.

It is important that the matrix component 150 be at least semi-solid andpreferably rigid during usage of the device 1, so as to support thetooth 113 in position while procedures are being performed on the tooth113. For this purpose, various thermally set materials or the like couldbe utilized wherein the component 150 is initially a resin or powderinto which the tooth 113 can be initially pushed or embedded after whichthe component 150 is heat set and solidified. Alternatively the matrixcomponent 150 may be a stick-type resin that forms a liquid when heatedand which can be dispersed into the sleeve 112, such as is illustratedin FIG. 7, and thereafter allowed to harden by drying, chemicalreaction, heating with subsequent cooling or the like. It is foreseenthat other types of matrix components may be used in accordance with theinvention. For the purpose of dispersion, a heating gun 155, such as aglue gun, distributes drops or a stream of conductive liquid or gelmaterial 156 into the sleeve 112 around the tooth roots 139 whichthereafter solidifies or hardens as matrix component 150.

A pin 160 is utilized to secure the sleeve 112 in a respective socket111. While it is foreseen that in some instances, the matrix 114 couldbe placed in a socket directly without a sleeve 112, such a sleeve 112is preferred as same allows for quick change out and reduces the timethat would otherwise be required to clean the hardened matrix out of thesocket.

The illustrated pin 160 is a thumb screw that has a threaded shank 163and flat head 164. The pin 160 is received through openings 167 in themanikin jaws 120 or 121, as is shown in FIGS. 4 and 8. The threadedshank 163 provides two functions. In particular, the shank 163 locks thesleeve 112 in position relative to a respective socket 111 and alsoprovides a metallic conductor that directly engages the highlyconductive component 148 when assembled, as shown in FIG. 8. The head164 also provides two functions. The head 164 allows a graspingstructure for a user to insert the pin 160 and further provides asurface that is comparatively shaped to receive an alligator clip 171,as will be discussed below.

It is foreseen that the tooth 113 can be inserted into the matrix 114 inthe sleeve 112 in a number of ways, but one alternative is shown inFIGS. 5 to 7. In particular, the crown 146 of the tooth 113 to bemounted is placed in an indentation 173 in a block 174 of wood, embeddedin a putty-like material, or the like. The highly conductive matrixcomponent 148 is placed over the root tips 139 and thereafter the rootsleeves 149 are placed over the tooth roots 139 and the component 148.Then the matrix holding sleeve 112 is placed over the lower part of thetooth 113 with the sleeve lower end 132 engaging an upper surface 175 ofthe block 174. The liquid material 156 that forms the second matrixcomponent 150 is then deposited in the sleeve 112 so as to preferablycover the root tips 143, the conductive component 148 and the protectors149, so as to secure the tooth 113 in the sleeve 112. The sleeve 112with the tooth 113 secured therein is then placed in a selected socket111 and the pin 160 is used to secure the sleeve 112 in the socket 111.The pin 160 preferably also touches a respective highly conductivecomponent 148 in which case the remainder of the matrix 114 that iscomponent 150 does not have to be electrically conductive. If the pin160 is not positioned to touch the highly conductive component 148, thenthe matrix component 150 must also be electrically conductive.

After the sleeve 112 is placed in the socket 111, a student 170 connectsan apical position locator 180 to the device 100. In particular thestudent 170 uses an elongate reamer or probe 181 that has a shaft 182sized to extend through a selected root canal 138. The shaft 182 is aconductive metal and is electrically joined by an alligator clip 184attached to a lead 185 or the like to the main body (not shown) of thelocator 180. The alligator clip 171 with a lead 187 is attached to thepin head 164, as is seen in FIG. 4. After opening the tooth crowns 164by a well known process, the student then practices finding the bottomof the root canal 138 in the manner previously described. In anendodontic procedure, the finding of the apex of the root canal 138 isaccompanied by removal of the pulp 141 and enlargement of the pulp orroot canal 138 to the depth determined by the above described procedure.Thereafter, subsequent root canal procedures are performed.

It is foreseen that when a patient has a tooth that has a metallicfilling or crown extending into or near the pulp chamber or root canal,it may be necessary to use a probe that is insulated over at least theportion of the shaft that would engage the filling or crown. For thispurpose part of the shaft may be coated with nonconductive material. Itis also foreseen that a hook, eye or the like may be joined to andextend outward from the probe shaft to facilitate connection of thelocator device and especially an alligator clip.

It is also foreseen the manikin may be constructed of conductivematerial as well as the entire matrix 114 in which case it is notnecessary that the pin be conductive, but only that the locator leadhook onto or otherwise join with the manikin jaw somewhere therealong.It is also foreseen that the sleeve holding the tooth may be held inplace by something other than a pin or set screw. For example, a coverhinged to the manikin or a moveable hook could be used to hold thesleeve in the manikin during training procedures.

It is foreseen that the highly conductive material may include a fillerof conductive carbonaceous material, including furnace black, channelblack, acetylene black, graphite fiber and carbon fiber; conductivefiber materials, including aluminum, nickel, copper, iron and stainlesssteel fibers; and metal coated fibers, including metallized glass,metallized graphite and metallized plastic fibers; conductive metalpowders, including metallic flakes, powder and milled or groundmetallized glass; and other conductive materials, including conductiveorganic polymers, glues, sponges, epoxies, paints, alginates and thelike. A binder for the highly conductive component may be chosen fromthermoplastic resins, including acrylic, polyvinyl chloride,polypropylene, polyethylene terephthalate, polystyrene, abs(acrylonitrite butodiene styrene resin), polyphenylene ether,polycarbonate, styrene and ethylene vinyl acetate; polymers, includingbis-gma, TEGAMA and HEMA; and others, including plasters, yellow stone,clay and the like.

The following radiopaque materials may be added to some embodiments:barium sulfate and substantial concentrations of metal fillers such asnickel, stainless steel and the like.

It is foreseen that a conductive portion of the tooth holding matrix canalso be a mixture of conductive materials including water, glycerine andother conductors, especially a percentage of from about 1 to 80% byweight in combination with a filler or gelatin selected from clay,silica, gum, agar, alginate and the like. Further, the conductivematerial is preferably water with sodium hypochlorite, EDTA(ethylenediaminetetraacetic acid), conductive aluminum compounds,conductive calcium and sodium salts, conductive carbonate compounds,conductive basic compounds and the like in a range from 1 to 80% byweight with the remainder being binder or miscellaneous fill.

The following examples are provided to illustrate the invention and arenot intended to be limiting on the scope or interpretation of theclaims:

EXAMPLE I

Highly conductive matrix components were produced in accordance with theinvention having the following formulation by weight:

Composition A ethylene vinyl acetate 68% carbon powder 30% steel fiber2%

Composition B flour 45% salt 15% water 35% oil 5%

The highly conductive matrix component Composition B was applied toroots of these teeth, as is shown in FIG. 5 and a root sleeve of plastictubing was placed about Composition B, as is shown in FIG. 6.Composition A was then placed about the tooth root in a sleeve, such assleeve 112, as is shown in FIG. 7, and a procedure was performed usingan apex locator as described in the last embodiment to find the distancefrom the crown to each tooth root apex. Two other procedures wereperformed on each of the teeth to determine root length which were byx-ray measurement and by in vitro measurement. The results are providedin Table 1.

TABLE I Test Result: Root length Root length Root length by in vitro inmm by x-ray in mm apex locator in mm Anterior teeth 23 23 23 Two rootbicuspid 20, 20 20, 20 20, 20 Three root molar 19, 19, 19 19, 19, 19 19,19, 19

EXAMPLE II

Matrix conductive components of compositions C and D were prepared andtests were performed in the same manner as in Example I. The CompositionD was applied directly to each root apex and the Composition C was usedto surround and support each tooth and around Composition D.

Composition C Clay 70% Carbon-coated fiber 30%

Composition D Agar 30% Salt 10% Water 55% Oil 5%

Table II illustrates the results of testing:

TABLE II Root length Root length Root length by in vitro in mm by x-rayin mm apex locator in mm Anterior teeth 23 23 23 Two root bicuspid 20,20 20, 20 20, 20 Three root molar 19, 19, 19 19, 19, 19 19, 19, 19

EXAMPLE III

Matrix conductive components of compositions E and F were prepared andtests were performed in the same manner as in Example I. The CompositionD was applied directly to each root apex and the Composition E was usedto surround and support each tooth and around Composition F.

Composition E acrylic 70% carbon powder 30%

Composition F Gum 30% Salt 15% Water 50% Oil 5%

TABLE III Root length Root length Root length by in vitro in mm by x-rayin mm apex locator in mm Anterior teeth 23 23 23 Two root bicuspid 20,20 20, 20 20, 20 Three root molar 19, 19, 19 19, 19, 19 19, 19, 19

EXAMPLE IV

Matrix conductive components of compositions G and H were prepared andtests were performed in the same manner as in Example I. The CompositionH was applied directly to each root apex and the Composition G was usedto surround and support each tooth and around Composition H.

Composition G epoxy 70% conductive sponge 30%

Composition H Glycerine 77% Salt 5% Water 15% Carbopol 3%

TABLE IV Root length Root length Root length by in vitro in mm by x-rayin mm apex locator in mm Anterior teeth 23 23 23 Two root bicuspid 20,20 20, 20 20, 20 Three root molar 19, 19, 19 19, 19, 19 19, 19, 19

Composition I Ground Stone 60% Carbon Powder 40%

Composition J Alginate 60% Water 40%

TABLE V Root length Root length Root length by in vitro in mm by x-rayin mm apex locator in mm Anterior teeth 23 23 23 Two root bicuspid 20,20 20, 20 20, 20 Three root molar 19, 19, 19 19, 19, 19 19, 19, 19

The test results for each of the Examples I to V indicate that locatingroot length apexes utilizing devices in accordance with the inventionhave essentially the same accuracy as direct measurement (which cannotbe accomplished in a living patient) and x-ray.

It is foreseen that teeth may be imbedded in the matrix by severaldifferent methods. The matrix can initially be powder, soft, pliable orthe like and the tooth pushed into the matrix. The matrix may be pouredabout the tooth as seen in the third embodiment. Furthermore, it isforeseen that the highly conductive component of the matrix may belocated only about the tooth root and surrounded by a second componentor the highly conductive component may completely fill a sleeve sizedfor insertion in a socket or a container, or the highly conductivecomponent may be a layer having less conductive material above and/orbelow the highly conductive component, including a thin layer of matrixfixing material that forms a substantially solid layer of matrix nearthe top of the tooth.

As will be apparent to persons skilled in the art, various additionalmodifications, adaptations and variations of the foregoing specificallydisclosed embodiment and method for training in the use of an apicalposition locator may be made without departing from the objectives andscope of the present invention. Various modifications and changes may bemade to the embodiment disclosed herein by those skilled in the art andsuch are contemplated by the present invention and are to be understoodas included within the spirit and scope of the appended claims.

Fourth Embodiment

Illustrated in FIGS. 10 through 13 is a fourth embodiment of a dentaltraining aid in accordance with the present invention and generallyindicated by the reference numeral 200. The fourth embodiment includeselements of the first three and reference is made to the first threeembodiments for greater detail.

The dental training device 200 includes a tray or structural support203, three training inserts 204, 205 and 206 and a securing plate 207.

The structural support 203 is generally in the shape of a human jaw andin conjunction with the inserts 204, 205 and 206 provides a user withthe feel of working on a human. It can be either an upper or lowerportion of the mouth and can be used separately or in combination with asecond unit in a manikin of the type shown in FIG. 4.

The support 203 includes a peripheral wall 210 extending upward from alower and generally flat base 211 to a contoured end 212. A central andrearward portion 214 of the base 211 extends upwardly and has a pair ofspaced and threaded bores 216 that extend downward vertically from a topthereof. The remainder of the base 211 is covered by a relatively thinmetal conductive plate 220 that is somewhat crescent or horseshoe inshape and which preferably receives all of the training inserts 204, 205and 206 thereon in touching relationship. The plate 220 includes a metalconductive ring 225 that extends through and protrudes outwardly fromthe support 203. The plate 220 has an upper surface 228 that is below anupper surface 229 of the base portion 214.

The support wall 210 has an interior facing aperture or slot 230 foreach insert 204, 205 and 206 that also face the inserts 204, 205 and 206respectively when placed on the support 203 and which are used forsecuring the inserts 204, 205 and 206 in the support wall 210 asdescribed below.

The present embodiment includes three inserts 204, 205 and 206 althoughit is foreseen that two or more than three could be used in accordancewith the invention. The illustrated inserts 204, 205 and 206 aredesigned to provide practice and instruction to a student training indental procedures.

In the present embodiment, insert 204 is especially designed fortraining in repair of tooth decay procedures, insert 205 is designed fortraining in crown and bridge procedures and insert 206 is designed fortraining in root canal procedures. Each of the inserts 204, 205 and 206are modular and can be replaced with other units that provide trainingfor the same or different procedures. In this manner, the student canacquire inserts for a single aid 200 device that can be used multipletimes to teach different procedures and can be assembled in such amanner, as shown, to allow training or testing on multiple procedures atthe same time or a plurality of training sites for a single procedure.In particular, in some uses, all of the inserts may be for the sameprocedures.

The insert 204 includes a base structure 235 that simulates the rightrear third of the lower jaw. It includes apertures, sockets or openings238, 239, 240 and 241 for teeth 250 to be used in training for treatingtooth decay. The openings 238, 240 and 241 are designed to receive asingle tooth 250 each. The opening 239 is wider than the others andreceives multiple teeth 250, so that the teeth 250 therein can be set tosimulate a close positioning.

A tongue 255 extends outwardly from the insert 204 and is shaped andsized to be received in one of the slots 230. Each of the openings 238,239, 240 and 241 extend vertically part way through the insert 204. Glueor adhesive may be utilized to hold the tooth and a surrounding matrix250 in the opening 238. A bore 261 extends through the base 235 andallows the alternative use of screw to hold the tooth 250 in the socketor opening 238. In use each of the openings 238, 239, 240 and 241receive at least one tooth 250 for performing repair of dental decayprocedures as described before. The insert 204 has an inward facing lip257 near the bottom thereof for securing in place. A front 260 of theinsert 204 has a recess 261 therein. Teeth 250 are placed in each of theopenings 238, 239, 240 and 241 in the matrix 262 that gives slightlywith pressure so as to simulate the ligaments that are attached to liveteeth. Preferably, the matrix 262 is at least partly constructed ofrubber, silicon or the like to provide some degree of flexure. It isforeseen that the top of the matrix 262 can be solid with the tooth 250and only the bottom of a flexible material.

The insert 205 is designed for crown and bridge work and in the presentembodiment simulates the portion of the jaw normally holding the front 6lower teeth of the mouth with the intent to use the two outer teeth forsupporting a bridge. In particular, openings 266 and 267 are providedwhich receive and hold artificial or real teeth which are then ground bythe student to provide supporting pegs 270 and 271, as shown in FIG. 11.The student prepares a bridge 275 with artificial teeth 276, 277, 278,279, 280 and 281 that then set on and are adhered to the pegs 270 and271 in a conventional manner. A drape 284 of polyurethane, silicon,rubber or the like extends over the insert 205 and simulates theflexibility and structure of gum tissue, since it is important for thestudent to carefully interact with gum in crown procedures.

The insert 205 also includes an outward facing tongue 290 that ispositioned to fit in one of the slots 230 and an inwardly facing lip291. On opposite ends of the insert 205 are position outward extendingpegs 293 that are sized and shaped to be received in respective recessesin inserts 204 and 206 such as recess 261 in insert 204.

The insert 206 simulates the left side of the lower rear third of thejaw and includes six openings 300, 301, 302, 303 and 304 which are eachsized to receive a tooth 308 and do extend to the bottom 307 of theinsert 206. Each of the openings 300, 301, 302, 303, 304 and 305 aresized and shaped to receive a unit such as unit 310 which includes atooth 308 and a surrounding conductive media 311. The units 310 areglued or otherwise affixed in the openings 300, 301, 302, 303, 304 and305. The teeth 308 are preferably real teeth having a root canal. Thestudent performs root canal procedures on the teeth 308 in the mannerdescribed before. The top part of the media 311 does not need to beconductive, but the lower portion onto which the tooth 308 root canalopens must be conductive between the tooth 308 and the plate 220. Thematerial of the media 311 engages the plate 220 so as to provide aconductive path between the bottom of each tooth root and the ring 225.The insert 206 has a tongue 318 and a lip 319 similar to like structurefound on the insert 204.

The securing plate 207 is sized and shaped to be secured to the base 211using screws 324 set in apertures 325 that are received in bores 216 inthe support 203. The securing plate extends outwardly toward each insert204, 205 and 206 so as to cover the lips 257, 291 and 319 and so as tosecure the inserts 204, 205 and 206 in the support 203 when secured inplace by the screws 324.

In use the various inserts are used in the manner shown in FIG. 11. Anelectrode 330 attached by an alligator clip 331 to the conductive ring225 when root canal procedures are performed in any of the inserts 204,205 or 206. The inserts 204, 205 and 206 are changed out as needed forother procedures or when expended to start new procedures.

It is foreseen that each insert would have an inwardly directedextension plate that could be attached by a single thumb screw, bymultiple screws or the like to the support 203 and could replace theplate 207. Also, it is foreseen that an electrode could be attached tothe plate 220 in a different manner than is shown which could replacethe conductive ring 225.

An alternative embodiment is shown in FIGS. 13 and 14 and designated astraining device 350. Device 350 has a base 353 with a peripheral rim 354and a base plate 355. The plate 355 has multiple locator holes 360 toenable connection to a dental manikin. The holes are arrayed in atriangular arrangement with a center hole so that the plate 355 isadapted for fitting to a variety of dental manikins. These manikins havepins in the oral cavity and the plate 355 slides onto the locator pins.The base 353 is a holder for mandible segments 365, which may be severalin number, such as three or four and which are interconnected, as bytongue and groove connectors. The segments 365 have sockets 366 holdingartificial teeth 368. The teeth 368 are removable and replaceable foruse in training for root canal procedures.

The mandible segments 365 are removable from the holder base 353 forcleaning and detailed work. A holder mechanism 370 extends across a rearof the mandible segments 365 to hold them in place against theunderlying plate 355. Because the rear segments are interconnected withthe front segments, the front segments are also held in place. Adhesivesor magnetic strips may be used to aid in holding the front segments inplace. The mechanism 370 in the illustrated example consists of a centerpost 372 extending upwardly from a centered hold through the base plate355. A lower stop in the form of head 373 stops the post and a topwinged tee 375 provides an upper stop. Other forms of lower stops couldbe used such as keeper ring, cross pins, magnets or the like. Similarly,other forms of upper stops could be used including, for example, keeperrings, pins, friction or screw caps magnets or any such stop. A coilspring 377 biases a crossbar 380 to an upper position. The crossbar 380has a longitudinal slot 383 accommodating the tee end 375 so that thepost 372 can be rotated and allow the crossbar 380 to be locked down orreleased up. The crossbar 380 has ends 390, 391 engaging the mandiblesegments 365 to hold them down. Exemplary measurement for the slot 383and tee end 375 are 10-30 mm.

The hold down mechanism 370 provides an efficient and secure method ofretaining the teeth and gum segments on the base plate 353 yet allowingease of removal when intended.

A further alternative embodiment of a dental training device 400 isshown in FIGS. 16 and 17. The device 400 may be utilized in conjunctionwith a manikin device such as that shown in FIG. 4 or as a stand alonetraining aid or tool for teaching a dental practitioner to performvarious procedures or for demonstrating actual dental procedures onwhole teeth suitable for receiving the procedure during testing or thelike.

Shown in FIGS. 16 and 17 is only a lower device 400; however, if thedevice 400 were used with a manikin structure, such as shown in FIG. 4,then an upper mirror image of the device 400 may also be utilized withthe same or different teaching block inserts, as described below.

The device 400 includes a lower support or tray 402 with at least twotraining inserts 403 and 404. The tray 402 has a relatively thin bottomwall 410 with a generally planar insert receiving and engaging surface411 surrounded by a peripheral ridge 415 that generally surrounds thesurface 411. At least one screw receiving aperture 417 for securinginserts 403 and 404 extends vertically through the wall 410 and receivesa respective screw 418. The illustrated device 400 includes a centralaperture 420 for attaching the device 400 to a manikin with a screw (notshown).

The inserts 403 and 404 are sized, shaped and designed to mimic aportion of the gum line mouth of a patient and include a gum region 423,teeth 424 and empty cavities 425 for teeth.

In the illustrated embodiment the teeth 423 are fixed and non removableand either provide a dentist or trainee with environment within to work,or are utilized for procedures that do not require destruction orpartial destruction of the teeth, or are placed on a disposable insertthat may be discarded at the end of usage and replaced by another.

The cavities 425 are designed to receive teeth of the type illustratedand discussed with respect to FIGS. 5, 6, 7, 11 and 13 wherein eachtooth may be inserted and secured therein. Subsequently a procedure maybe performed on the tooth, such as a root canal or filling, thateffectively destroys or modifies the tooth or renders the tooth unusablefor further procedures. In this case, the used tooth can be removed froman associated cavity 425 and replaced with another tooth. Yet further, atooth can be selected for a specific procedure and permanently securedin the cavity 425. The teeth 424 or those teeth in the cavities 425 maybe real human teeth or artificial teeth. After the procedure iscompleted, the entire insert 403 or 404 is removed and replaced ormodified by change out of teeth and reinserted.

The present embodiment is configured to receive three inserts, includingrear insert 403 and front insert 404, along with a mirror image rearinsert. Each insert 403 and 404 has a generally flat under surface 430.The insert 403 has a threaded aperture 431 for receiving a respectivescrew 418. The insert 403 also includes an undercut region 436 foroperably interlocking with insert 404. The insert 404 has a projection440 that is operably received in the region 436 of the insert 403 whenassembled and a forward projecting peg 442 that is received in theperipheral ridge 415 when assembled. In this manner, the rear inserts,such as insert 403 are secured to the tray 402 by the screws 418 and thecentral or front insert 404 is secured to the tray 402 by the peg 442and the projections 440 being received in the rearward insert regions436.

The inserts 403 and 404 are thereby held in place on the tray 402 andpresent teeth, such as teeth 424 and teeth in cavities 425, so as to beavailable for simulating actual dental procedures by a dentist intraining, teaching, testing or the like. In this way a dentist canperform and/or demonstrate these procedures in a manner that is quitesimilar to performing then on a human subject, but without requiring alive subject.

After the procedures are complete, the inserts, such as inserts 403 and404 can be removed and replaced by new inserts having teeth 424 forsimulating the same or different procedures and/or the teeth in certaincavities 425 can be removed and replaced. The inserts 403 and 404 allowthe dentist to perform full dental procedures. The inserts 403 and 404are abuttingly received on the tray 402 and are both secured to the tray402 and to each other by securing the rearward inserts 403 to the traywith screws and the forward insert 404 to the rearward inserts 403 byinterlocking structure.

Preferably the tray 402 and inserts 403 and 404, except for teeththerein, are constructed of a material that does not impede x-rays, sothat the dentist can use x-rays or the like in assisting with proceduresperformed on the device 400. The screws 418, while x-ray opaque arepreferably low profile (near the bottom or away from the teeth 424) andnot likely to impede the process.

Shown in FIGS. 18 and 19 is yet another embodiment of a dental trainingdevice 460 that is similar in many ways to the previous device 400. Thedevice 460 has a tray 462 and inserts 463 and 464 that are similar totray 402 and inserts 403 and 404 except with respect to the followingdifferences.

In particular, the rear inserts 463 and front insert 464 are removablysecured to the tray 460 by magnets 470. The magnets 470 of theillustrated embodiment are located in the tray 460 and are preferablycomparatively high gauss ceramic magnets that are snugly received insuitably sized apertures 472 in the tray 462 hld therein by adhesive461. The magnets 470 of the illustrated embodiment are secured by theadhesive 461 to the tray 462; however it is foreseen that the magnets470 could be secured by other suitable means such as screws and thelike. Located in the inserts 463 and 464 are blocks 480 of material suchas iron that is attracted to magnetic fields. The blocks 480 are eachpositioned opposite the magnets 470. While the blocks 480 of theillustrated embodiment are glued by adhesive 481 into the inserts 463and 464 associated therewith, it is foreseen that such could be securedby other means such as screws. The blocks 480 are located in the lowerpart of the inserts 463 and 464 so as to have a low profile and notinterfere with x-ray techniques or the like. Further, while the magnets470 are illustrated in the tray 462 and the blocks 480 in the inserts463 and 464, this could be in part or totally reversed, so that at leastsome of the magnets are located in the inserts. It is also foreseen thatthe blocks 480 could also be magnets.

It is to be understood that while certain forms of the present inventionhave been illustrated and described herein, it is not to be limited tothe specific forms or arrangement of parts described and shown.

1. A dental training device comprising: a) a tray having a generallyplanar base portion having a periphery and an upwardly extending walljoined with said periphery of said base portion; b) a plurality ofinserts; each of said inserts being simultaneously removably securableto said tray; each of said inserts abutting against adjacent inserts andjoining to form a gum line; each of said inserts including at least twosockets; and c) a plurality of tooth structures, each tooth structurebeing sized and shaped to be received into one of said sockets, therebysimulating a human tooth and being sized, shaped and constructed so asto allow a dental practitioner to perform at least one dental procedurethereon.
 2. The device according to claim 1 wherein: a) said baseportion has an insert-engaging surface and said upwardly extending wallabuts against said inserts.
 3. The device according to claim 2, furthercomprising: a) a pair of magnetic connectors, one of said magneticconnectors being a magnet and the other of said magnetic connectorsbeing a plate attracted to said magnet; wherein: b) one of said magneticconnectors is associated with said insert-engaging surface; and c) theother of said magnetic connectors is associated with a tray-engagingsurface on said insert.
 4. The device according to claim 2, furthercomprising: a) at least one screw for removably securing at least one ofsaid inserts to said insert-engaging surface.
 5. The device according toclaim 2, wherein: a) said insert-engaging surface includes a conductiveplate; and b) at least one of said tooth structures includes aconductive media configured and arranged for electrical connection withsaid conductive plate.
 6. The device according to claim 1 wherein: a) atleast one of said inserts is directly secured to said tray and a secondof said inserts is indirectly secured to said tray by interlocking withsaid first insert.
 7. The device according to claim 1 wherein: a) atleast one of said inserts is secured to said tray by at least one screw.8. The device according to claim 1 wherein: a) said tray includes afirst of a magnet and a block attracted to a magnet; and b) at least oneof said inserts includes a second magnet and a second block attracted toa magnet; said insert being positioned so said magnet attracts saidblock and removably secures said at least one insert to said tray whensaid at least one insert is placed on said tray.
 9. The device accordingto claim 1 wherein: a) said plurality of inserts includes first andsecond inserts sized and shaped to simulate a gum of correspondingportions of a human mouth.
 10. The device according to claim 1 wherein:a) said inserts, when on said tray, combine to simulate the complete gumline associated with a jaw of a human mouth.
 11. The device according toclaim 1 wherein said plurality of inserts includes: a) at least oneposterior insert sized and shaped to simulate a posterior portion of ahuman gum; and b) at least one anterior insert sized an shaped tosimulate an anterior portion of a human gum.
 12. The device according toclaim 1 wherein said plurality of inserts includes: a) at least one leftinsert sized and shaped to simulate a left portion of a human gum; andb) at least one right insert sized an shaped to simulate a right portionof a human gum.
 13. The device according to claim 1 wherein: a) saidplurality of inserts includes an interchangeable insert.
 14. The deviceaccording to claim 1 wherein said tray is sized and shaped to simulateat least a portion of a human jaw.
 15. The device according to claim 14wherein said human jaw is an upper jaw.
 16. The device according toclaim 15 wherein said inserts simulate an upper gum.
 17. The deviceaccording to claim 14 wherein said human jaw is a lower jaw.
 18. Thedevice according to claim 17 wherein said inserts simulate a lower gum.19. The device according to claim 1, further comprising: a) a secondtray.
 20. The device according to claim 19, further comprising: a) ahinge sized, shaped and constructed to articulatingly connected saidfirst tray to said second tray.
 21. The device according to claim 1,wherein: a) at least one of said tooth units includes an extracted humantooth.
 22. In a dental teaching device simulating a human mouth forperforming dental procedures; the improvement comprising: a) a trayhaving a base portion having a generally planar upper surface and aperiphery; and b) a plurality of individual interchangeable inserts thatare removable and interchangeable with other inserts simultaneouslypositioned on said tray to provide a simulated mouth of a patient; saidinserts being removably securable to said tray; each of said insertspresenting with at least two tooth sockets, each socket being sized andshaped for holding a tooth unit capable of having a dental procedurepreformed thereon.
 23. The device according to claim 22 wherein: a) atleast one of said inserts is securable to said tray by a screw.
 24. Thedevice according to claim 22 wherein: a) at least one of said inserts issecurable to said tray by a cooperating pair including a magnet and ablock attracted to said magnet that are attached respectively to saidtray and to said at least one insert.
 25. The device according to claim22, the improvement further comprising: a) a second tray articulatinglyattached to said tray.
 26. The device according to claim 22, theimprovement further comprising: a) a plurality of securablyinterchangeable tooth units.
 27. The device according to claim 26,wherein: a) at least one of said tooth units includes an extracted humantooth.
 28. The device according to claim 22, wherein: a) said baseportion includes an electrically conductive plate; and b) at least oneof said tooth units includes an electrically conductive media inelectrical contact with said plate.
 29. A method of performing simulateddental procedures comprising the steps of: a) providing at least a pairof inserts, each insert having at least two tooth units sized, shapedand constructed for having an actual simulated dental procedureperformed thereon; b) providing an insert receiving tray; c) securingsaid inserts to said tray such that said inserts abut each other andjoin to form a gum line; d) thereafter, performing said dentalprocedures on at least a first tooth unit provided for performing theprocedures; and e) thereafter, removing said inserts.
 30. The methodaccording to claim 29 including: a) replacing said first insert with anew insert; b) wherein said first insert includes said first tooth unitthat was modified during the procedure performed thereon.
 31. The methodaccording to claim 29 including: a) providing a socket on a firstinsert, wherein said socket is sized and shaped for releasably matingwith a tooth unit; b) securing a tooth unit in said socket; c)performing one of said procedures on said tooth unit in said socket; andd) thereafter replacing said tooth unit in said socket with a new toothunit.